Relief-governor for air-compressors.



No. 686,779. Patented Nov. I9, |9ol. G. F. STEEDMAN.

rHELIEF GOVERNOR FOR AIR CMPBESSORS.

(Application lod Mar. 25. 1901.)

3 Sheets-Sheet I.

1pm/EN TOL Z'yizmyu (No Model.)

No. 686,779. Patented Nov. I9, |90I.

G. F. STEEDMAN.

RELIEF GOVERNOR' FUR AIR GQMPRESSUBS.

(Application led Mar. 2L 1901.)v

3 Sheets-Sheet 2'.

(No Model.)

No. 686,779. Patented Nov. I9, l90l. G. F. STEEDMAN.

RELIEF GOVERNOR FOR AIR CDMPRESSORS.

(Application med Mar. 25. 19m.)

3 Sheets-$heet 3.

(No Model.)

'UNrTED STATES PATENT OFFICE.

GEORGE F. STEEDMAN, OF ST. LOUIS, MISSOURI.

RELIEF-GOVERNOR FOR AIR-COMPRESSORS.

SPECIFICATION' forming part of Letters Patent No. 686,779, dated November 19, 1901.

Application filed March 25, 1901. Serial No. 52.84%. (No model.)

To all whom, t may concern.-

Be it known that I, GEORGE F. STEEDMAN, a citizen of the United States, residing at the city of St. Louis, in the State of Missouri, have invented a certain new and useful Improvement in Relief-Governors for Air-Compressors, of which the following is a full, clear, and exact description, such as will enable others skilled in the art to which it appertains to make and use the same, reference being had to the accompanying drawings, forming part of this specification, in which- Figure 1 is a sectional view illustrating my improved governor in its normal operative position. Fig. 2 is a similar view showing the parts in position wherein the auxiliary reliefvalve is open to establish communication between the discharge-passage from the compressor and the atmosphere, and Fig. 3 is a similar view showing the main and auxiliary relief-valves opened. Fig. 4 is a top plan View of an air-compressor, showing my im proved relief-governor arranged in the pipe leading from the compressor to the reservoir. Fig. 5 is a side elevational view of the same.

This invention relates to a new and useful improvement in a relief-governor for air-compressors, the objects being to construct a governing device which shall be economical of the power necessary to drive the compressor, absolute in its action, mechanical in its details, and one which is not liable to get out of repair.

With these objects in view the invention is embodied in the novel construction, arrangement, and combinations of parts hereinafter described, and set forth in the claims.

In the drawings, A indicates a dischargepipe leading from the compressor W into the relief-valve casing, and B represents a discharge-pipe leading from said relief-valve casing to the reservoir or other suitable receptacle for the compressed air.

C represents the blow-od pipe or vent-pipe leading from the relief-valve casing and discharging into the atmosphere at any desired point. This pipe is shown by dotted lines in Figs. 1 and 2.

D indicates the relief-valve casing, which is preferably provided With caps CZ for the valves contained therein. This casing is formed with a passage or chamber E, which which is arranged a valveseat,) in which opening operates a check-valve G, whose function is to admit air from chamber E into chamber F Whenever the pressure in E exceeds F, said valve obviously closing, if permitted to do so, when pressure in chamber F exceeds that in the chamber E. For the purpose of explanation I will refer to this valve G as opening toward the reservoir, and it will be understood that While I have shown an ordinary Winged check-valve a Hap-valve will answer the same purpose.

H indicates a valve which controls an opening leading from chamber E, which opening when valve H is raised establishes comm unication between chamber E and the blow-off or vent pipe C. This valve H is shown as a winged valve, although other forms of valves may be employed, if desired, and is normally closed by the pressure of the compressed air in the chamber E on its upper surface. When valve H is closed, valve G is designed to be open, so that the compressed air discharged from the compressor passes throughchambers E and F and on to the reservoir.

Secured to one side of casing D and preferably in axial alinement with valve H is a cylinder I, carrying a piston J, Whose rod j extends through casing D in line with thc valve H. This cylinder is preferably insulated from casing D by a rubber or other suitable non-heat-conducting washer t' for the purpose of preventing said cylinder from becoming heated and carbonizing the leather in piston J. As shown, cylinder I is secured to a flange d, extending from the casing D, which ange is open at one side for the reception of a lever K, which is pivoted to said flange, a spring L bearing upon one member of said lever for the purpose of forcing the same into engagement with the piston J and holding said piston in the outer end of cylinder I, as shown in Fig. 1. The other, or, as I will term it, the outer, end of lever K eX- tends under a rod k, which enters casing D (suitable packing being provided) in axial alinement with valve G. Through the in- IOS) strumentality of spring L, lever K, and rod 7c valve G is normally held open, as shown in Fig. 1,' whilevalve H is closed.

Fig. l represents the normal lor running position of the governor, and it will be noticed that valve G acting simply as a checkvalve, being raised from its seat, as above described, Will not move with every pulsation of the compressor, and so does not wear itself out. The valve H is never moved except when called upon to open communication between chamber E and the atmosphere to relieve the compressor from the work of forcing air into the reservoir when the reservoir has received its maximum pressure.

For purposes of distinction I will refer to the valve H as the main relief-valve, said valve carrying an auxiliary relief-valve M, having a seat preferably in the upper face of the valve H, the stem m of said auxiliary relief-valve extending through and projecting below the stem of the main valve H. By the above construction it will be noticed that the valve M is nested in the valve H. Openings are arranged under the seat of the auxiliary relief valve, whereby when said valve is raised from its seat, as shown in Fig. 2, communication is established between the chamber E and the pipe C, which leads to the atmosphere, this without changing the position of the main valve H. This auxiliary reliefvalve might be termed a pilot-valve, in that it is operated in advance of the main valve, and by being operated in advance of the main valve relieves pressure above the main valve, which enables the main valve to be operated with Very little effort. I consider this important, in that the small area of the auxiliary valve enables the same to be operated quickly, and by relieving the pressure above the main valve the main valve is not only sensitive, but the parts designed to be operated may be made comparatively light. Furthermore, it requires but little energy to move the main'valve after the auxiliary valve is unseated. I will also state that the piston-rod 7' after raising the auxiliary valve contacts with the main valve for the purpose of raising both valves, as shown in Fig. 3.

I will now describe the mechanism for operating the valves H and M when the maximum pressure in the reservoir is reached or exceeded.

N indicates a pipe leading from the reservoir X or other place where it is desired to prevent the pressure from exceeding the maximum limit, said pipe supplying pressure to a chamber n. Arranged in this chamber is a valve O, consisting of a suitable head, wings, and valve proper, over which head is arranged a spring 0, whose tendency is to move said valve from its seat; but, due to the pressure on said head, said valve is normally closed. The port or opening controlled by this valve leads under the piston-'rod j. Valve O, before referred to, bears at one end against a diaphragm Q, forming the end wall of chamber n.

R indicates an extension secured to the valve-casing, containing a spring-pressed plunger R', bearing against the outer face of the diaphragm Q, the tension of which spring is sufficient under ordinary circumstances to keep the valve O in a closed position. However, when the pressure in chamber n reaches its maximum, it will overcome the tension of this spring-pressed plunger, forcing said plunger back, permitting the spring o over the head of valve O to depress said valve from its seat. A follower r is introduced into the outer end ofthe extension R for the purpose of adjusting the tension of the spring fr', so as to regulate and adjust the pressure of the plunger-head against the diaphragm to accommodate the governor to various conditions by regulating the tension of spring fr to resist movement up to a certain pressure, beyond which the diaphragm will be forced outwardly against the pressure of said spring-pressed plunger and permit the valve O to be depressed froin its seat. Jam-nut or cap r" is preferably threaded on the follower r to engage with the same and the casing R, said follower being threaded in said casing. If desired, a lock may be provided for this cap r to prevent the pressure on the plunger-head from being changed by unauthorized persons who might unwittingly rotate the follower r.

Under normal running conditions the parts should occupy the position shown in Fig. 1; but should pressure in the reservoir reach its maximum a like pressure in chamber fn would overcome spring r' and depress valve O from its seat, thus establishing communication between pressure in chamber yn and the space under the piston.- This pressure would act to force the piston upwardly, as shown in Fig. 2, the rod of said piston iirst engaging the stem of the auxiliary valve, raising it from its seat and permitting pressure to flow under the main valve, after which continued movement of the piston in an upward direction would raise the main and auxiliary valves together, as shown in Fig. 3, permitting the pressure in chamber E to flow out through the pipe C. At the same time the lever K would permit the check-valve G to close, so as to prevent the pressure in the reservoir from escaping back through pipe C. Under these conditions no pressure can enter the revervoir through'the valve G on account of the pressure on the top of said valve, and the pressure in chamber E, having an easier escape, will pass through the pipe C, the parts remaining in this position as long as the pressure in the reservoir is sufficient to overcome the resistance of the spring pressed plunger behind the dia phragm. As soon as the pressure in the reservoir diminishes the spring-pressed plu-nger will assert itself and close the valve O, which thereby breaks communication between the chamber n and the space under the piston. The air under the piston now escapes through IOO IIO

a port 7 controlled by a leak-valve 8, which is in the form of a slotted bolt introduced into the valve-casing, the slot in said bolt decreasing in depth toward the outer end, whereby when said bolt is screwed in or out the amount of leakage in the space under the piston may be adjusted. When the air under the piston has been exhausted, said piston will be forced down to its normal position lby the inner end of lever K and spring L bearing thereagainst. Pressure in chamber E will now act to seat the valves H and M, and spring L will act to raise the valve G. It will be noted, however, that valves H and M close before valve G is opened, there being considerable lost motion between the valves and the rods which raise the valves from their seats, so that it is impossible to raise all the valves from their seats at the same time.

Vhen there is pressure in the reservoir and for any reason it is desired to shut down the compressor, it is extremely hard to again start the compressor under a heavy load. I have provided a valve designed to be operated manually at the will of the operator, so that in starting the compressor should there be pressure in the reservoir valve G will be closed and valves H and M will be open, so that the compressor will have little or no work to do until it attains the proper speed, after which the manually-operated valve may be turned so as to permit valves H and M to seat themselves and valve G to be raised, as in the normal running conditions. l0 indicates this manually-operated valve, which closes a port 1l, opening in chamber n. When valve lO is open, pressure from chamber n enters through port l1 and passes through port 12 into the space behind the piston J, throwing said piston upwardly and elevating valves H and M from their seats. Whenever the compresser has attained speed, valve 10 is closed, and the pressure behind the piston leaks out through the valve 8, as above described, to exhaust the pressure behind piston J, so that valves H and M will close and valve G open.

I prefer to provide a port 14 behind the plunger R for the escape of leakage past the diaphragm and for accommodating the displacement of air due to the movement of the springpressed plunger R.

It will be observed that in the above construction the valves have little Work to do, and therefore will remain tight for a long time, and that it is impossible to waste any air from the reservoir by having both valves open at the same time. It is also impossible to stop up the discharge-pipe of the compressor, because even though the relief-valves were not operated the pressure will still enter the reservoir and not be confined to said discharge-pipe. The device is positive in its action, very sensitive, quick-acting, and practically automatic, requiring little or no attention, except when starting the compressor with pressure in the reservoir, which requires the manual manipulation of one valve,which should remain open a sufficient time to enable the compressor to attain speed. For illustration, the rod 7s may be omitted, in which event the valve G would not be held in its raised position but could seat itself by gravity or whenever the pressure in chamber E was less than F.

I am aware that minor changes in the construction, arrangement, and combination of the several parts of my device can be made and substituted for those herein shown and described without in the least departing from the nature and principle of my invention.

Having thus described my invention, What I claim, and desire to secure by Letters Patent, is-

l. The combination with a compressor and its delivery-pipe having a vent to atmosphere, of valves of different area exposed to pre'ssure, which valves are normally held seated by fluid-pressure to close such vent, and iiuidpressure mechanism for successively actuating said valves, said mechanism first raising the valve having the smaller area to relieve pressure above the valve having the larger area, to open the vent and establish communication therebetween and the compressor when the pressure delivered by the compressor has reached or exceeded the maximum; substan-f* tially as described.

2. The combination With a compressor and its delivery-pipe having a vent to atmosphere, of valves of different sizes having one side exposed to pressure, said valves normally closing the vent to atmosphere, and mechanism automatically set in action when the pressure delivered by the compressor has reached or exceeds a predetermined maximum for raising the smaller valve, and then causing the larger valve to be raised; substantially as described.

3. The combination with a compressor and its delivery-pi pe having a vent to atmosphere, of valves of dierent areas exposed to pressure, which valves are normally held seated by fluid-pressure to close such vent, fluidpressure mechanism controlling said valves and operating them successively, said mechanism iirst raising the valve having the smaller area to relieve pressure above the valve having the larger area, a connection from the reservoir for admitting pressure to said fluid-pressure mechanism to operate said valves to open the vent when the pressure delivered by the compressor has reached or eX- ceeded the maximum, and automatic means for releasing said admitted pressure after the operation of such fluid-pressure mechanism; substantially as described.

4. The combination with a discharge-pipe having a vent to atmosphere, of a valve H, a valve M nested in valve H, said valves clos ing said vent, a valve G which is normally open, a piston for raising the valve M for admitting pressure to the vent and relieving the pressure above the valve H, said piston then raising the valve H and making the full area IOO IIO

of the vent available for the passage of Iiuidpressure, means coperatiug with said piston and the valve G whereby, when the piston is in its lowermost position, valve G is elevated and vice versa, said valve G being supported when in open position, and a valve for admitting pressure under the piston when the pressure in the pipe reaches or exceeds the maximum; substantially as described.

5. The combination with the discharge-pipe of an air-compressor, of valves G, H, and M arranged therein, a piston for successively operating the valves M and H and raising the former against the pressure in the pipe, a spring-pressed Valve O for controlling the pressure behind the piston, and a pipe leading from the delivery-pipe to the chamber in which said spring-pressed valve is located, whereby, when the pressure in said deliverypipe reaches or exceeds a predetermined maximum, the valve O is operated to admit pressure under the piston, substantially as 'described.

6. The combination with a delivery-pipe having a vent to atmosphere, of valves M and H for closing said vent to atmosphere, iiuidpressure mechanism for operating said Valves successively when the pressure in the delivery-pipe reaches or exceeds the maximum, said fluid-pressure mechanism including a piston and a valve for admitting pressure behind said piston, and a manually-operable valve for admitting pressure behind said piston independently of the fluid controlled valve, substantially as described.

7. The combination with a compressor and its reservoir, of a pipe connecting the two, a valve-casing D forming part of said pipe, a

check-Valve G in said casing permitting air to flow from the compressor to the reservoir and preventing the ioW of air in the reverse direction, valves M and H in the casing between the check-valve G and the compressor, said valves M and H normally closing a vent leading to atmosphere, a lever K for raising the check-valve G, a piston J with which said lever K coperates, a cylinder I attached to casing D, iu which cylinder the piston J is l0- cated, an automatic valve O, a diaphragm c0- operating with said valve, a spring behind said diaphragm, and a leak-valve 8, substantially as described.

8. The combination with a compressor and its reservoir, of a pipe connecting the two, a valve-casing D forming part of said pipe, a check-valve G in said casing permitting air to fiow from the compressor to reservoir and preventing the flow of air in the reverse direction, valves M and H arranged in casing D between the check-valve G and the compressor, said valves M and H normally closing a vent to atmosphere, a lever K, a plunger 7s arranged under valve G, with which the lever K coperates, a piston J, a cylinder I in which said piston is arranged, an automatic valve O, a spring-pressed diaphragm coperating with said valve O, a leak-valve 8, and a by-pass valve l0, substantially as described.

In testimony whereof I hereunto aftix my signature, in the presence of two witnesses, this 23d day of March, 1901.

GEORGE F. STEEDMAN.

Witnesses:

GEORGE BAKEWELL, HARRY L. AMER. 

